* {
  margin: 0px;
  padding: 0px;
}

section {
  width: 800px;
  height: 300px;
  background-color: pink;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}
/* nth-child 选择器匹配属于其父元素的第 N 个子元素，不论元素的类型。 */
section .top {
  height: 100px;

  background-color: red;
}
section .bottom {
  height: 100px;
  /* background-color: chartreuse; */
  display: flex;
  justify-content: space-between;
}
section .bottom .left {
  width: 100px;
  height: 100px;
  background-color: aqua;
}

section .bottom .right {
  width: 100px;
  height: 100px;
  background-color: aqua;
}
